l. Field of the Invention
This invention relates to material handling vehicles and, more particularly, to such vehicles having a steering and hitch assembly between a tractor portion and a trailer portion thereof.
2. Description of the Prior Art
There are in existence many material handling vehicles which employ a tractor for both pushing and pulling a trailer. One such vehicle would be a vehicle for use in a mine with low ceilings and limited area for maneuvering the vehicle wherein the operator is positioned on the tractor, facing sideways, and manipulates the tractor and trailer for loading and unloading the trailer through an articulating and oscillating hitch connection between the tractor and the trailer.
In current vehicles a support member projects from the trailer into the area between the tractor and the trailer and has, in the central portion thereof, an opening in which an oscillation housing is oscillatably mounted in a bearing. The housing is pivotally connected to the tractor and has the drive shaft that extends from the tractor passing therethrough for connection with the differential on the trailer. The oscillation housing is a yoke-like member and has structure on outwardly extending ears for connection to steering cylinders projecting from the tractor. Due to the type of mounting of the oscillation housing in the support member and the pivotal connection to the tractor, the tractor is permitted to oscillate about the axis of the drive shaft and pivot about an axis transverse to the oscillation axis, both oscillation and pivoting being relative to the trailer. An operator manipulates controls to elongate or foreshorten the steering cylinders, thereby turning the tractor and trailer relative to each other about the vertical axes of the pins. At the same time, as the vehicle traverses terrain, the tractor and trailer can oscillate relative to each other about the axis of the drive shaft.
The hitch assembly of current vehicles takes up considerable space and thereby requires the vehicle to be longer than may be desired. In mines and other areas where there is only limited space available for maneuverability, it is desirable to have the length of the vehicle as short as possible without sacrificing payload capacity of the trailer or engine capacity of the tractor.